Preheat the oven to 350 degrees F.

To Make the crust, combine the flour, salt and sugar in a bowl. Cut the cold butter into the flour mixture with a pastry blender and reduce butter to pea-size crumbs. Add water to combine it with the seasoned flour and butter. Do not over work the dough.

Roll the dough into a circle ¼ inch thick. Transfer to 9-inch pie pan, tucking the edges of excess dough under, rather than trimming off.

Brush the crust edge with egg wash, puncture the bottom of the crust several times with a fork. Lay a piece of parchment or foil over the crust and use pie weights or dried beans to weigh down the crust. Refrigerate for 30 minutes, then bake at 350 degrees F for 20 minutes, or until it begins to brown.

Prepare the limon filling. Start by whisking together the egg yolks with the corn starch in a bowl.

Combine the sugar, water, butter, lemon juice and zest in a saucepan. Bring to a simmer, then remove from heat. Slowly pour the hot mixture into the bowl with the egg yolks, whisking continuously until fully incorporated. Return the mixture to the saucepan, and simmer over medium heat to thicken. Pour filling into pre-baked crust while warm.

Create the thickening starch for the meringue by combining the cornstarch with cold water in a saucepan. Add the boiling water and simmer until thickened. Remove from heat and let cool fully.

Using a stand or hand mixer, beat egg whites until foamy. Slowly add the combination of vanilla, sugar, and cream of tartar to the egg whites until fully incorporated. Beat to stiff peaks. Add the thickened starch one spoonful at a time, whipping at a high speed to incorporate. Spread meringue over pie filling while still warm.

Bake at 350 degrees F for 10 minutes or until lightly browned.